Restroom trailer for a 3-day festival: generator size for AC in October?

Question

We're planning a fall festival for 2026 in the South, expecting about 500 people a day over a Friday-to-Sunday weekend. We want to rent a medium-sized restroom trailer, something with four stalls and air conditioning. It's an outdoor event on a grass field with food vendors and beer sales, so we know we'll need the AC running all three days. The location has no power hookups, so we need a generator.

I need to know the total power draw for the trailer's systems, especially the air conditioner, to size the generator correctly. What's the typical amperage or wattage for a four-stall trailer's AC unit, and how much extra capacity should we plan for to run it safely for the whole festival?

Nina R. · Answer

A four-stall restroom trailer's air conditioner typically draws around 15 amps (1800 watts) on startup and 10 amps (1200 watts) running, but you need a generator rated for at least 4000 watts to handle the AC plus lights, exhaust fans and water pumps. Always size the generator for the startup surge, not just the running load.

Restroom trailers need continuous power. The AC compressor cycles on and off, but lights and ventilation run constantly. Add capacity for a margin of safety, generators run more efficiently and last longer when not maxed out. A 5000-watt generator gives you headroom for a hot afternoon or a faulty unit drawing more power.

Rent a generator with enough fuel capacity for the whole event or plan for refueling. Diesel generators are quieter and more fuel-efficient for long runs. Check with your rental company, they often provide the generator as part of the trailer package and know the exact power requirements for their units.

For a 500-person festival with alcohol, plan on more than one restroom trailer or a mix with standard units. A single four-stall trailer won't be enough for peak hours. Cluster units with ADA compliance and handwash stations near food and beer areas.

Restroom trailer for a 3-day festival: generator size for AC in October?

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